The term cable winch generally includes devices which apply a certain tensile or hoisting force onto a corresponding object by means of a cable. The cable mostly is wound up on a cylindrical drum driven by a motor.
Up to now, the winches have been constructed of individual components. The input shaft of the spur-gear transmission is of the continuous type, wherein at the end the main drive of the cable winch is attached. In case of a possible defect at the main drive, a safety braking system is actuated and an emergency drive possibly is activated for the emergency operation of the winch. In known luffing winches, this emergency drive can be coupled to the second shaft end via a switchable clutch.
Such cable winches have been used for years as versatile hoisting and pulling winches in a broad spectrum of applications. Due to the design of these luffing winches as compact cable winches, the construction of these winches could be improved in terms of ruggedness and simplicity. The overall size of the compact winches was significantly shortened by a planetary transmission protected inside the drum. Motor, brake, transmission and drum are arranged coaxially to each other. A disadvantage of this construction, however, consists in that the switchable clutch of the emergency drive at the opposite shaft end only is possible to a limited extent or even is impossible.
Therefore, it is the object of the present invention to provide an alternative solution for coupling an emergency drive to a compact cable winch, as required.
This object is solved by the combination of a winch, in particular a luffing winch, with a winch drum, at least one main drive driving the drum shaft and at least one emergency drive driving the drive shaft in case of emergency, characterized in that at least one emergency drive can be coupled to the driven wheel of the drum shaft as required via at least one mechanical transmission element or a mechanical transmission unit.
According to claim 1, there is proposed a winch with a winch drum, a main drive driving the transmission input shaft, and an emergency drive driving the transmission input shaft in case of emergency. When the winch according to the invention, in particular the luffing winch, is designed as compact winch, winch drum and main drive preferably are arranged coaxially to each other. Furthermore, when designed as compact winch, the driving transmission as well as the braking device preferably likewise are arranged coaxially to the main drive and the winch drum. Particularly preferably, a planetary transmission is interposed between main drive and winch drum for driving the compact winch.
According to the invention, at least one mechanical transmission element or at least one mechanical transmission unit, in particular in the form of at least one intermediate gear, is provided, in order to couple the emergency drive to the driven wheel of the transmission input shaft, as required. The power transmission from the drive wheel of the emergency drive accordingly is effected via the interposed intermediate gear to the driven wheel of the transmission input shaft. Instead of one or more intermediate gears, the power transmission in accordance with the invention also can be effected via chain elements, toothed belts or the like.
Advantageously, the intermediate gear is shiftably mounted for coupling in and out. Preferably, the intermediate gear is shiftably mounted in direction of its shaft axis. Accordingly, the intermediate gear can be shifted into a position coupled in, which provides for a power transmission from the drive wheel of the emergency drive to the driven wheel of the transmission input shaft. The movement of the intermediate gear into the position coupled out leads to an interruption of the power transmission from the emergency drive to the transmission input shaft.
Coupling the provided intermediate gear in and out preferably is effected via a lever mechanism to be actuated manually or automatically. The lever actuation brings the intermediate gear in engagement with the drive wheel or the driven wheel. It is conceivable that the lever mechanism is accessible for the user from outside. When a defect occurs at the main drive, the user can actuate the lever quickly and easily and switch the winch over to the emergency drive.
To prevent an inadvertent shift in position of the intermediate gear during operation of the winch, at least one locking means preferably is provided for fixing the intermediate gear position. For example, an engagement of the emergency drive into the drive train of the shaft thereby is inhibited in normal operation. Furthermore, it is ensured that during the emergency operation the flux of force from the emergency drive to the transmission input shaft is interrupted by a displacement of the intermediate gear. Particularly preferably, a locking bolt to be actuated manually is suitable as locking means, which inhibits any displacement of the intermediate gear along its shaft axis.
An optimum power transmission advantageously is ensured by a roof-like toothing of the intermediate gear and of the driven wheel of the transmission input shaft. Furthermore the roof-like toothing allows a smooth positioning of the intermediate gear for engagement into the driven wheel of the transmission input shaft.
In a preferred embodiment of the invention the drive wheel of the emergency drive includes a hexagon as an additional possibility for adjustment. This adjustment possibility allows the optimization of the flux of force from the emergency drive to the transmission input shaft. In particular, the engagement of the drive wheel of the emergency drive into the intermediate gear can be readjusted and optimized.
For communicating the respective position of the intermediate gear to the winch controller, one or more inductive transmitters are provided. In this way, it can in particular be detected whether or not the intermediate gear is in engagement with the drive wheel and driven wheel of the emergency drive train. One or more inductive transmitters expediently are arranged in the region of the intermediate gear shaft.
When the main drive is blocked mechanically in case of a defect, means for decoupling the main drive from the drive train of the transmission input shaft preferably are provided. In particular, the main drive can be disengaged from the drive train of the transmission input shaft by means of slotted spacer bushes, so as to inhibit the non-positive connection. Preferably, the means for decoupling or the slotted spacer bushes effect a displacement of the main drive in direction of the shaft axis, in particular in a direction opposite to the transmission input shaft. The main drive accordingly is moved away from the transmission input shaft on the shaft axis.
It is particularly advantageous when the gear wheels are coated. The emergency running properties (dry running) generally are improved thereby. The coefficient of friction thereby is minimized, and noise and wear are reduced.
The present invention furthermore is directed to a construction machine or a lifting device which includes at least one winch, in particular luffing winch, according to any of the aforementioned combinations of features.
Further advantages and details of the invention will be explained in detail below with reference to drawings.